I originally bought a Mag Trainer without the remote shifter. This add on makes training much easier and, particularly interval training, where you're increasing and decreasing resistance in your training. It installed easily in minutes and made a world of difference in resistance levels and my ability to effectively train indoors.

I bought the Mag Trainer without the magnetic shifter initially and found my self either getting frustrated with the resistance or interrupting my workout to get off and adjust it. The remote shifter addressed the issues and I absolutely recommend it. It was a bit confusing to install, but I figured it out easily enough.